Mail Block - general

One of our clients is concerned that all-of-a-sudden several domains are blocking her campaigns. This happened in the last campaign sent. Previous campaigns got through no problem. The reason given in her report is:

Mail Block - General (MB)

Indicates that the recipient's email server is blocking email from our email server.
Example: "550 Message REFUSED by peer"

Why would this happen and how can I resolve the problem for my client?

JD JD, 7 years ago

It may be better to submit this question to our support team so that we can investigate the specific client account, campaign content and the domains that may be blocking that campaign.  In short though, this could be caused by content in your clients campaign, custom settings on the receiving server (that may have been triggered by the subject line or spammish content) and the filters those servers use.  Thanks!

Campaign Monitor Support
bopjo1 bopjo1, 7 years ago

Thanks, I submitted a support request earlier today and am waiting to hear back.

The strange thing is that the content of her campaign has not changed in months and we've sent countless emails with the same subject line to those domains and they got through perfectly fine. Now, all of a sudden we are blocked....

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